The development of unmanned aircraft, an increasingly vital weapon in modern warfare, is centered in the region and growing rapidly as billions in federal money pours in each year.

Reporting from Poway — The cars begin rolling through the security checkpoints before dawn. Here, in a sprawling complex amid the craggy rock outcroppings of north San Diego County, 3,300 workers are building a new generation of weapons central to the military's vision for modern warfare.

FOR THE RECORD: Drone planes: Captions for two photographs that accompanied an article in the Sept. 12 Section A about the growing demand for unmanned aircraft used outdated names for the locations of two air bases. The former George Air Force Base is now called Southern California Logistics Airport. The former March Air Force Base is now March Air Reserve Base. —

This is where General Atomics Aeronautical Systems makes the Predator and Reaper drones, robotic planes that can thread the rugged mountains of Pakistan, capture video images of terrorist hideouts and launch 500-pound Hellfire missiles to blast them apart.

The company's 1.9-million-square-foot facility is a showcase for Southern California's drone industry, which employs an estimated 10,000 people. The fast-growing business is fueled by Pentagon spending — at least $20 billion since 2001 — and billions more chipped in by the CIA and Congress.

Seeing an almost limitless market, dozens of defense contractors — Boeing Co. and Lockheed Martin Corp. among them — are now vying to get in on the action. They are building surveillance drones the size of insects that can fly through open windows, and others as big as jetliners that can skim the stratosphere.

Soon, experts say, the military and private companies alike will have fleets of robotic planes that can do just about everything piloted aircraft can do, such as carrying cargo and engaging in aerial combat.

"It is the most hotly sought-after weapon system in a generation," said Loren Thompson, a military policy analyst for the Lexington Institute, a think tank in Arlington, Va.

The industry is centered in Southern California, a testament to the region's rich aerospace history and the skilled workforce that arose with it.

It's also the product of big-money lobbying and pork-barrel politics.

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Thomas J. Cassidy Jr. stood on the windswept tarmac of Adelanto Airport in the Mojave Desert, pitching the wonders of the Predator drone to a dozen scientists and firefighting officials.

For Cassidy, this was the B list. The Pentagon was always seen as the primary customer for the Predator, but early trials during the conflict in Bosnia hadn't gone well. The small aircraft, powered by a pusher propeller, was easily shot down by antiaircraft fire. Fighter pilots mocked it as a pricey model plane.

Cassidy, a gruff former Navy rear admiral, was hired by General Atomics to persuade his former comrades in the military to buy the Predator. Now he was looking for any customers he could find. The Predator could be used to spot wildfires, he told his latest prospects. It could monitor global warming.

The audience listened politely — then scattered quickly when the demonstration ended. There were no takers.

It was Sept. 6, 2001. Five days later, the world changed.

"That's when the phone started ringing off the hook," Cassidy said.

With the terror attacks of Sept. 11, the military suddenly wanted a weapon that could search for and destroy Al Qaeda's mountain lairs. The Predator had its customer.

It was a turning point for General Atomics, and the company was poised to take full advantage of the opportunity.

Through its political action committee, General Atomics had been making friends in Washington since the early 1990s, giving nearly $3 million since 1998, according to the Center for Responsive Politics.

By comparison, the political action committee for Northrop Grumman Corp. in Century City gave $8.2 million over the same period. But Northrop is a giant, with 120,000 employees and $33 billion in annual revenue. Analysts estimate that General Atomics, which is privately held, has 4,500 employees and annual revenue of about $600 million.

Among those who received campaign money from General Atomics was former Rep. Randy "Duke" Cunningham, a San Diego-area Republican who in 2006 was sentenced to more than eight years in prison for accepting $2.4 million in bribes from two military contractors and evading income taxes.

General Atomics was not involved in that scandal. But it counted Cunningham among its favored friends, giving him a total of at least $35,000 for his campaigns from 1998 to 2006, and holding a 2004 fundraiser for Cunningham and other candidates at its corporate headquarters in San Diego.

Contributions tell only part of the story. From 2000 through mid-2005, General Atomics spent $660,000 —more than any other U.S. company — to pay for 86 trips for members of Congress, their spouses and aides to company facilities and overseas destinations, according to a study by the watchdog group Center for Public Integrity. Such junkets have since been banned.